Draft gear for railroad cars



Nov. 3, 1959 w. K. M cuRDY DRAFT GEAR FOR RAILROAD CARS 5 Sheets-Sheet 1 Filed May 7, 1956 INVEN TOR Zd/AA MM KMncfz/ear Arraemnfi Nov. 3, 1959 9 w, MacCURDY 2,911,113

DRAFT GEAR FOR RAILROAD CARS Filed May '7, 1956 5 Sheets-Sheet 2 IN VEN TOR.

MILL/AM K. MncCuim Nov. 3, 1959 Filed May 7, 1956 W. K. M CURDY DRAFT GEAR FOR RAILROAD CARS 3 Sheets-Sheet 3 William K. MacCurdy,

United States Pate 2,911,113 DRAFI GEAR FOR RAILROAD cARs MenloPark, Califi, assignor, by

mesne assignments, to Southern Pacific Company, San

Francisco, Calif., a corporation of Delaware Application May 7, 1956, Serial No. 583,116

11 Claims 01213-8 This invention relates to and in general has for its ob- -ject the provision of a draft gear for railroad cars constituting an improvement to the draft gear disclosed in my copending application, .Serial No. 467,118, filed two sets of plates against such relative movement, a hydraulic pump remote to said hydraulic press for actuating said :press, and means for actuating said hydraulic pump in response to the relative movement of said two sets of friction plates. V I

More specifically, the object of thisinvention is the provision of a draft gear, including a draft sill movably a mounted within a center sill; first and second relatively movable and interdigitated sets of friction plates mounted within the draft sill, one set being anchored to one sill and the other set to the other sill; a longitudinally extending, first inclined plane secured to one set of friction plates; and a spring-loaded dashpot secured at one end to the center sill and provided at its opposite end with a second inclined plane complementary to and coacting with said first inclined plane, whereupon the two sets of friction plates are compressedin response to the relative movement of said sills, said compression being under the control of the dashpot.

The invention possesses other advantageous features, some of which, with the foregoing, will be set forth at length in the following description where that form of the invention which has been selected for illustration in the drawingsaccompanying and forming a part of the present specification, is outlined in full. In said drawings, one form of the invention is shown, but it is to be understood that it -is not limited to such form, since the invention as set forth in the claims may be embodied in,

other forms.

Referring .to the drawings: v Fig. 1 is a fragmentary top plan view of the under- ,frame of a railroad car body embodying the objects of my More specifically, the draft gear disclosed in these drawings comprises a fabricated car frame center sill generally "designated by the reference numeral 1, and including a top 2 and sides 3, each provided with outwardly extending flanges 4.

Arranged for longitudinal movement within the confines of the center sill 1 is afabricated draft sill, boxice shaped in cross-section, generally designated by the reference numeral 5, and including a top 6, abottom 7, and opposed sides 8 and 9. As best shown in Fig. 2, the top 6 and bottom 7 are cut away as at 11, 12, 13, and 14 for purposes of accommodating the friction plate assembly to be presently described. Welded to the outer faces of the draft sill sides 8 and 9 adjacent the cut portions of the sill top and bottom are stiffening channels 15 and Welded to the underface of the center sill top 2 is a rectangular press plate 17, and welded to the four 001'- ners thereof and to the top 2 are four vertically depending posts 18. Receivable within the rectangular cage so formed by the posts 18 is a stack of friction plates 19, the posts 18 of course serving to restrain the plates against longitudinal movement relative to the car frame center sill 1. Welded to the center sill flanges 4 are transversely spaced mounting plates 21, and welded to and between the center sill top 2 and the mounting plates 21 are vertical cage sides 22 serving to confine or restrain the friction plates 19 against lateral or transverse movement.

Movable friction plate cradle assembly Welded to the inner faces of the sides 8 and 9 inwardly of the cutoutsll, 12, 13, and 14 are two sets of blocks or posts 23 and 24, and nested between and extending longitudinally beyond these posts is a stack of movable friction plates 25 interdigitated with the stationary friction plates 19. As best shown in Fig. 2, each end of each of the friction plates 19 is of tie form in vertical section, thereby to provide the end of each plate with a shoulder 26. Abutting .the shoulders 26 at each end of the plates 19 is a stackiof transversely extendingspacer bars 27 interdigitated with the plates 19. Welded to the lower edge of the draft sill sides 8 and 9 in vertical alignment with the spacer bars 27 are angles 28 extending inwardly within the confines of the draft sill and'therefore serving to support the two interdigitated sets of friction plates 19 and 25. Extending through the spacer 'bars 27 laterally of the friction plates 19 are vertically disposed tie rods 29, and threaded'thereto are nuts 31. From an inspectionof Figs. 2 and4, it will be seen that since the inner edges of the spacer bars 27 abut the posts 23, since the posts are fixed to the draft sill and since the outer edges of the spacer bars 27 engage the shoulders 26 of the friction plates 25, the latter are constrained to follow the movementofthe draft sill. More specifically, it is to be noted that if the draft sill moves to the left as viewed in Figs. 2 and 4, the posts 23 serve to pull the friction plates 25 to the left, whereas if the draft sill moves to the right, the posts 24 serve to pull the friction plates 25 to the right. Therefore, regardless of the direction of movement of the draft sill, the friction plates will always be under tension, and by reason of this construction, all tendency of the friction plates to buckle is obviated.

Dashpot assembly Bolted to the flanges 4 of the center sill 1 through I the intermediate mounting 21 are the transversely spaced flanges 35 of a depending stationary cylinder 36 of a dashpot generally designated by the reference numeral 37. Included as an integral part of the cylinder 36 is a bottom 38 provided with diametrically extending ledges or lugs 39 formed with spring seats 41. Slidable within the cylinder 36 and sealed thereto by a ring 42 is a cylindrical piston 43 closed at its upper end by an integral base member 44 and closed at its lower end by a plate or cap 45 secured thereto in any suitable manner. Formed on the base member 44 are longitudinally extending, diametrically opposed lugs 46 in vertical registration with the lugs 39, and formed therein are downwardly facing spring seats 47. Seated on and between each opposed pair of spring seats 41 and 47 is a compression spring 48 serving to upwardly bias the base member 44 and to carry the load of the friction plates. Secured to the base member 44 is a depending d rt guard or skirt 49 circumscribing the upper end of the cylinder 36 and having a running fit therewith. Threaded to the lugs 46, coaxially with the springs 48, are spring retainer pins 51, the lower ends of which pass with substantial clearance through holes 52 formed in the lower lugs 39; and threaded to the free ends of the pins 51 are nuts 53.

Dashpot metering mechanism Formed centrally of the dashpot cylinder bottom 38 is a threaded bore 55, and threaded therein is the barrel 56 of a metering pin 57, the barrel 56 being formed integral with the pin 57. Secured over the lower enlarged or stepped end of the bore 55 is a plug 58 provided with a bore extension 59 for the reception of the lower end of the metering pin 57. The contour of the upper end of the pin 57 is of reverse double conical form as indicated at 61 and 62, and the upper downwardly converging conical portion being arranged to positively clear a coaxial conical bore 63 formed in the cap 45. Prior to placing this device in operation it is filled with a liquid working medium to a level indicated by the line 64.

Inclined planes dashpot operating assembly Secured to the lowermost movable friction plate 25 centrally and extending longitudinally thereof is a pair of reversely inclined plates 75 and 76 symmetrically disposed with respect to the dashpot 37. Secured to and formed integral with the base member 44 of the dashpot piston 43, and extending upwardly therefrom, is a shoe 78 provided with reversely inclined surfaces or planes 79 and 81 complementary respectively to the inclined plates 75 and 76 and in sliding engagement therewith.

Operation of draft gear If for any reason the draft sill is subiected to an acceleration relative to the center sill, one of the plates 75 or 76 (depending upon the direction of movement of the center sill) will move over its associated complementary plane 79 or 81, thereby forcing the dashpot cylinder 43 downwardly and thus subjecting the working medium with the cylinder 36 to pressure. Simultaneously, the base member is subjected to an equal and opposite pressure with the result that the two sets of friction plates are squeezed or compressed together. Also simultaneously with this action, some of the working medium is forced upwardly between the metering pin 57 and its surrounding bore 63 into the cylinder43, thus relieving some of the pressure. The pressure to which the working medium is initially subjected depends of course on the movement of the plates 75 and 76, and this in turn depends upon the extent of the acceleration of the center sill relative to the draft sill. Likewise, the rate at which the pressure on the working medium is relieved dependsupon the extent of downward movement of the cylinder 43 relative to the fixed metering pin 57 and the contour of the pin. Here it should be noted that the springs 48 arenot relied upon to return the mechanism to its neutral position for this is done by means of springs associated with the sliding sill. The position of the metering pin 57 relative to its associated bore 63 can, of course, be altered at will be merely advancing the pin within its bearing plug 53.

As a result of this construction, it will be seen that the dashpot serves as the movable element of a press for compressing two relatively movable sets of friction plates; that the pressure to which the friction plates are subjected is responsive and proportional to the relative movement'between the center sill and the draft sill; and that such pressure is under the control of hi da$hpot.

I claim:

1. Draft gear for railroad cars comprising: a car frame center sill; a draft sill accommodated within said center sill for longitudinal movement relative thereto; a first set of friction plates mounted within said draft sill and anchored to said center sill against longitudinal movement relative thereto; a second set of friction plates mounted within and anchored to said draft sill against longitudinal movement relative thereto, the friction plates of said first and second sets of friction plates being interdigitated with each other and free to be compressed against each other and against a wall of said center sill; a longitudinally extending first inclined plane secured to said second set of friction plates for longitudinal movement therewith; and a fluid-type dashpot secured to said center sill adjacent said first inclined plane, said dashpot including a cylinder and a piston mounted for damped movement therein and provided with a longitudinally extending, second inclined plane complementary to, and in sliding engagement with said first inclined plane, thus exerting a force normal to the confronting faces of said interdigitated plates, said cylinder and said piston co-operating to define a pressure chamber, and mechanical means connecting said cylinder and said piston to said friction plates to mechanically transmit the pressure within said chamber to said plates to compress said plates against each other.

2. Draft gear such as defined in claim 1, wherein said piston is spring biased towards said first inclined plane.

3. Draft gear such as defined in claim 1, wherein said dashpot and said first and second inclined planes underlie said first and second sets of friction plates.

4. Draft gear such as defined in claim 1, wherein said dashpot is suspended from said center sill.

5. Draft gear such as defined in claim 1, wherein said dashpot includes an orifice and the flow of fluid through the dashpot orifice is under the control of a tapered pin extending through such orifice.

6. Draft gear such as defined in claim 1, wherein said dashpot includes an axially movable, transverse separating wall provided with a dashpot orifice and wherein the flow of fluid through said orifice is under control of a tapered pin extending therethrough.

7. Draft gear for railroad cars comprising: a car frame member; a draft member paralleling said car frame member and contiguous thereto; a first set of friction plates supported by said car frame member in parallelism therewith; means mounted on said car frame member for restraining said first set of friction plates against movement along said car frame member; a second set of friction plates fixed to said draft member and interdigitated with said first set of friction plates, said first and second sets of friction plates forming a stack of friction plates; a first pressure plate mounted onsaid car frame member over one face of said stack of friction plates; an inclined pressure plate fixed to said second set of friction plates over the opposite face of said stack of friction plates; a fluid-type dashpot fixed to said car frame member and underlying said inclined pressure plate, said dashpot including a cylinder and a piston mounted for damped movement in said cylinder, and said piston being provided with an inclined face complementary to and in sliding engagement with said inclined pressure plate, thus exerting a force normal to the confronting faces of said interdigitated plates; and means for resiliently urging said piston towards said stack of friction plates, said cylinder and said piston co-operating to define a pressure chamber, and mechanical means connecting said cylinder and said piston to said pressure plates to mechanically transmit the pressure within said chamber to said pressure plates to compress said stack of friction plates.

8. Draft gear for a railroad car comprising a car frame member; a draft member mounted on said car frame member for movement relative thereto longitudinallyof said car, cooperating means comprising relatively movable elements, one of said elements attached to said draft member, and the other of said elements attached to said frame member, said cooperating means defining coengaging friction surfaces so disposed that upon movement of said draft member relative to said car frame member and longitudinally of said car said co-engaging friction surfaces generate a friction force opposing such movement, other cooperating means on said members effective in response to such movement of said draft member relative to said car frame member to press said friction surfaces together to increase the frictional force generated therebetween opposing such movement, said other cooperating means including a dashpot mounted on one of said members and comprising a fluid cylinder, a piston disposed within said cylinder, and means for controlling the flow of said fluid to develop a cushioning force which resists movement of said piston relative to said cylinder, means mounted on the other of said members and engaging said dashpot to effect said movement of said piston relative to said cylinder in response to said movement of said draft member relative to said car frame member, and mechanical means interconnecting said dashpot and said first named cooperating means to mechanically transmit said cushioning force to said first named cooperating means to increase the pressure between said friction surfaces in response to movement of said piston relative to said cylinder.

9. Draft gear as defined in claim 8 wherein said cylinder and said piston define a variable volume pressure chamber, and said fluid flow control means defines fluid outlet passage means communicating with said pressure chamber and of variable effective cross-sectional area.

10. Draft gear for a railroad car comprising a car frame member, a draft member mounted on said car frame member for movement relative thereto longitudinally of said car, a first set of friction plates, means supporting said first set of friction plates on said car frame member and restraining said plates against movement therealong, a second set of friction plates, means securing said second set of friction plates to said draft member for movement therewith, said second set of plates being interdigitated with said first set of plates to form a stack of friction plates, cooperating means on said members for compressing said stack of friction plates in response to movement of said draft member relative to said car frame member and longitudinally of said car to increase the pressure between adjacent plates of said stack, said cooperating means comprising a dashpot mounted on one of said members and including a fluid cylinder, a piston disposed within said cylinder, and control means for controlling the flow of said fluid so as to develop a cushioning force which resists movement of said piston relative to said cylinder, means mounted on the other of said members and engaging said dashpot to effect said movement of said piston relative to said cylinder in response to said movement of said draft member relative to said car frame member, and mechanical means interconnecting said dashpot and said stack of friction plates to mechanically transmit said cushioning force to said stack to thereby compress said stack of friction plates.

11. Draft gear for a railroad car comprising a car frame member, a draft member mounted on said car frame member for movement relative thereto longitudinally of said car, first and second cooperating means on said members defining co-engaging friction surfaces so disposed that upon movement of said draft member relative to said car frame member and longitudinally of said car said co-engaging friction surfaces generate a friction force opposing such movement, other cooperating means on said members effective in response to such movement of said draft member relative to said car frame member to press said friction surfaces together to increase the frictional force generated therebetween opposing such movement, said other cooperating means including a dashpot mounted on one of said members and comprising a fluid cylinder element, a piston element disposed within said cylinder element, and means for controlling the flow of said fluid so as to develop a cushioning force which resists movement of said piston element relative to said cylinder element, one of said dashpot elements being secured to said first cooperating means, cam means mounted on said second cooperating means and engaging the other of said dashpot elements to effect movement of said piston element relative to said cylinder element in response to said movement of said draft member relative to said car frame member, and mechanical means including said one of said dashpot elements and said cam means cooperating to mechanically transmit said cushioning force to said first-named cooperating means to increase the pressure between said friction surfaces in response to movement of said piston relative to said cylinder.

References Cited in the file of this patent UNITED STATES PATENTS Courson Dec. 16, 1902 Dickerson Aug. 5, 1930 OTHER REFERENCES 

